1. Field of the Invention
This invention relates to a disc ejecting structure, and more particularly to a disc ejecting structure for, for example, a disc player such as a compact disc player, a laser disc player or the like.
2. Description of Related Art
For example, in a compact disc player used at a place at which it is easily exposed to vibration, shock or the like, such as a mounted-type compact disc player which is adapted to be mounted on a vehicle such as a car or the like, it is required to transfer a compact disc in the disc player for loading while keeping the disc safe as shown in FIG. 1. Such transfer permits the disc to be positively and safely loaded on a turntable of the disc player without being adversely affected by vibration or shock.
Now, a conventional disc transfer mechanism which is widely used for such a compact disc player will be described hereinafter with reference to FIG. 1. A disc transfer mechanism shown in FIG. 1 includes a housing 20 and a turntable 22 arranged in the interior of the housing 20. The housing 20 is provided on the front portion thereof with a disc port 24. Also, the disc transfer mechanism includes a transfer means or roller 26 which is arranged so as to be rotatable in both directions and positioned between the turntable 22 and the disc port 24. When a disc 28 is to be loaded in the disc player, the disc 28 which is inserted through the disc port 24, as shown in FIG. 2, is vertically interposed between the transfer roller 26 and a support member 30 arranged vertically opposite to the transfer roller 26. Then, the transfer roller 26 is rotated in one direction to transfer the disc 28 to a position above the turntable 22. In order to ensure that the disc 28 is accurately positioned above the turntable 22, a pair of positioning pins 32 are arranged at the rear section of a disc transfer passage defined in the housing 20. Such arrangement of the positioning pins 32 permits the peripheral edge of the disc 28 to be abutted against the pins 32 during the loading operation, to thereby align a central hole 34 of the disc 28 with the turntable 22. Then, the transfer roller 26 is lowered through a suitable lifting means (not shown) to lower the compact disc 28 onto the turntable 22 and then the disc is clamped or chucked by a clamping or chucking means (not shown), resulting in being ready for playing-back. When the disc 28 is to be ejected from the disc player, it is released from the clamping means and then the transfer roller 26 is raised by means of the lifting means to raise the disc 28. Subsequently, the transfer roller 26 is rotated in the other direction to transfer the disc 28 from the turntable 22 to a predetermined ejection completing position defined on the side of the disc port 24.
The most important trouble which is encountered with such a disc player loaded with a disc would be a failure in ejection of the loaded disc from the player. In order to prevent this type of trouble, the disc player is demanded to exhibit a function of positively ejecting the disc by repeating the disc ejecting operation, when the operation is failed although one ejection command is made or when the disc is not positively transferred to the ejection completing position although the ejecting operation takes place. For this purpose, the compact disc player including the disc transfer mechanism shown in FIGS. 1 and 2 employs an ejection detecting mechanism of the type that a timing of a disc injection operation which is carried out by a drive means such as a cam of a disc driving section, its gear or the like or the completion of the injecting operation is detected. More specifically, a mechanism is employed which is adapted to detect the position of a cam for lifting the disc.
Unfortunately, the conventional ejection detecting mechanism, as will be noted from thw foregoing, is adapted to indirectly detect completion of the disc ejecting operation through a timing of the drive means. Such construction of the mechanism causes the disc ejection to be erroneously detected, even when it is actually failed due to any difficulty although the drive means is actuated. Alternatively, it fails to detect the disc ejecting operation or the completion of the operation due to a failure in the timing of the drive means although the disc is actually fully ejected. The former is caused when repeating of the ejecting operation is not carried out, whereas the latter results in the actuation of the drive means being uselessly repeated.
It is widely known in the art that such disadvantages are also encountered with a disc player employing a disc transfer mechanism and/or an ejection detecting mechanism similarly constructed.
Thus, the conventional disc transfer mechanism fails to positively confirm or judge whether the disc is actually transferred to the ejection completing position or the disc ejecting operation is effectively accomplished, resulting in failing to positively eject the disc or useless repeating of the disc ejecting operation.
Also, in the prior art, a timing at which the completion of the disc ejecting operation is detected is determined by counting a predetermined length of time. Accordingly, when the disc strikes against any obstacle during the ejecting operation, the time elapses before the disc ejection operation is completed, so that the transfer roller 26 is often stopped before the disc reaches the ejection completing position. This leads to a failure in ejection of the disc from the disc player, resulting in interfering with loading of another disc in the disc player. Also, an attempt of forcibly removing the disc from the disc player or disc ejecting mechanism causes damage to the disc and/or application of overloading to the drive or loading roller 26, so that both disc and mechanism are broken.
In order to eliminate the problem, a disc loading device is proposed which is provided with an ejection completion detecting sensor for detecting whether the ejection is fully completed. Nevertheless, such an approach has important disadvantages. More particularly, if any force or vibration is accidentally or erroneously applied to the disc when removing the disc which has reached a disc ejecting position, it is undesirably loaded again in the disc loading device or disc player.
Also, the conventional disc transfer mechanism constructed as shown in FIGS. 1 and 2, as described above, is suitably used for a mounted-type disc player because it exhibits relatively satisfactory operability even under vibratory conditions. Recently, the demand of consumers on compact discs is diversified with rapid spread of the compact discs, leading to manufacturing of a compact disc of a diameter as small as 8 cm (8 cm compact disc) which is called a single CD in addition to the existing compact disc of 12 cm in diameter (12 cm compact disc). The 8 cm disc corresponds to an analog single disc of 17 cm in diameter. The appearance of the 8 cm disc causes some problems. More particularly, the conventional compact disc player is constructed so as to be accommodated to only the existing 12 cm compact disc, to thereby fail to distinguish the 8 cm compact disc and 12 cm compact disc from each other. Therefore, playing-back of the 8 cm compact disc requires the use of an exclusive adapter therefor, resulting in the operation being highly troublesome and the player being costly.
In order to eliminate the foregoing problem, a disc loading or transfer mechanism is proposed which includes a stopper arm for positioning a compact disc in place and holding it on a turntable. The stopper arm functions to detect any pressing force applied to thereto by a compact disc loaded in the mechanism to mechanically discriminate it, to thereby move between an operation position for a 12 cm compact disc and that for a 8 cm compact disc for the loading operation. Unfortunately, the proposed mechanical disc discriminating means is highly complicated in construction and fails to accurately discriminate a disc depending upon force of the disc applied thereto during the loading operation. Such a disadvantage is encountered with various disc players which is adapted to play back two or more discs difference in size, other than the compact disc player.
Further, it is proposed that the conventional disc transfer structure is provided with a single sensor, which is arranged between the disc port 24 and the transfer roller 26 for detecting the completion of loading of the disc 28. For example, such a sensor may comprises a photosensor arranged so as to be positioned slightly outside the outer periphery of the disc 28 when it is placed on the turntable 22. The sensor is adapted to exhibit a detection mode when it detects that something obstructs the sensor and a non-detection mode when there is nothing to obstruct the sensor. Thus, when the sensor takes the detection mode and then exhibits the non-detection, the structure judges that the disc is placed on the turntable 22, to thereby detect the completion of insertion of the disc and start the chucking means, resulting in completing the loading.
However, such conventional construction causes some disadvantages. More particularly, when any accident such as the insertion of a foreign article other than a disc into the structure, the lateral movement of a disc near the disc port 24, the drawing-out of a disc after slight insertion of the disc through the disc port 24 or the like which is sufficient to actuate the sensor occurs, the mode of the detection sensor is changed from the detection mode to the non-detection mode, to thereby cause the clamping means to uselessly carry out the disc clamping or chucking operation, resulting in the disc, the components of the structure and the like being damaged and/or failed.
Moreover, in the conventional disc transfer structure, the transfer roller 26 is constantly upwardly urged by means of a spring. Thus, in order to interposedly hold the disc between the transfer roller 26 and the support member 30 for the loading operation, it is required to downwardly force the transfer roller 26 to insert the disc between &he transfer roller and the support member and push the disc into a gap therebetween by force, so that a feeling of the operation may be deteriorated. In order to avoid the problem, it is desired that the rotation of the transfer roller 26 is started before the disc is inserted into the transfer roller and the support member, so that the loading is started at the time when the disc is inserted therebetween, to thereby improve the feeling. Unfortunately, if the structure fails to move the disc to a position where the disc is inserted between the transfer roller and the support member even when the transfer roller is thus rotated, the transfer roller continues to rotate while failing to engage the disc, resulting in a drive motor continuing to actuate. This causes excessive load to be applied to the motor, leading to damage to the motor and a failure in playing-back of the disc.